Investigators are trying to puzzle out what caused an explosion and fire that killed two people and tore through a residential area of Indianapolis, displacing scores of residents, authorities said today.

The damage is estimated at $3.6 million, with two homes leveled, five homes expected to be demolished and 26 more unlivable, said Adam Collins, deputy director of code enforcment for Indianapolis.

David Edds, the superintendent of the Greenwood Community School Corporation, said a second-grade teacher at Southwest Elementary School, lived in one of the homes leveled by the blast, and he thinks she may have died. The school district, on the border of Indianapolis, will delay the start of classes for two hours Monday so that counselors could be called to the school if the death is confirmed. The teacher was married but had no children, Edds said.

Authorities have not released the names of the two people killed.

"There's a significant number of homes that have sustained damage, including two that have been completely destroyed. No cause has been ruled out," said Marc Lotter, a spokesman for Indianapolis Mayor Greg Ballard.

"The investigation is ongoing," he said. He added that seven people had been injured in the explosion, which left a large debris field. The origin of the blast was near 8415 Fieldfare Way, in the south part of Indianapolis, according to an Indianapolis Fire Department release.

U.S. Rep. Andre Carson, D-Ind., who represents the area, said he went to the church where the new donation headquarters is and area Homeland Security officials told him a bomb and a meth lab have been ruled out as causes.

The two homes exploded just after 11 p.m. Saturday, sparking fires in two others and damaging at least two dozen homes on the south side of Indianapolis, said Lt. Bonnie Hensley, a spokeswoman for the Indianapolis Fire Department.

City officials inspected more than 120 homes, with 80 of them affected to one degree or another, and 31 of those with major damage, said Collins, the code enforcement official. Of those, five will have to be demolished and 26 cannot be lived in for an indefinite period, Collins said.

"It looks like a war zone here right now," Hensley said.

Police have so far been unable to identify the two adults who died, a spokesman said this afternoon.

Jan Able, who lives nearby, said she believes the victims, a couple, lived in the home next door to where the blast occurred.

A woman in her 40s and her 12 -year-old daughter who live in the home where the blast originated were in Ohio at the time, said Able.

Able's daughter and son-in-law live a few streets from Able, so she and her husband are staying with them.

Able said it’s a "very good neighborhood" full of professionals, including doctors, architects, nurses.

The blast originated near 8415 Fieldfare Way, according to the fire department release.

From his bedroom a block away, 47-year-old software engineer Chris Patterson felt the walls of his home shake. The force of the explosion shattered a glass sliding door in his home, he said.

Patterson said despite the grim situation, his spirit was bolstered by the efforts of his neighbors and first responders and has no plans to move away.

“I am freaked out, definitely, but I don’t think we want to move. We really like this neighborhood. I went to church this morning and I feel blessed because of how fast emergency people responded and the way our whole neighborhood pulled together,’’ Patterson said.

“I’m actually more inclined to stay.’’

Patterson was allowed back into his home about 1:10 p.m.

More than 100 firefighters responded to the two-alarm fire, according to a fire department statement.

Officials evacuated about 200 people to a nearby elementary school, where the Red Cross sheltered about 20 of them for the night. Others spent the night at friends' homes or with family, and officials planned to take the rest to the Southport Presbyterian Church.

As of late Sunday morning, approximately 60 cases of water and Gatorade were outside the school and a police spokesman said donations are pouring in, including toiletries, doughnuts and pizza.

Firefighters brought the fire under control by 12:30 a.m. Sunday but were still putting out hotspots afterward, Hensley said.

From his bedroom a block away, 47-year-old software engineer Chris Patterson felt the walls of his home shake. The force of the explosion shattered a glass sliding door in his home, he said.

"It felt like something had hit our house,” Patterson said.

Patterson and his wife stepped outside, where they found other neighbors in the street and an orange glow in the distance.

Another neighbor who lives in the newer subdivision where the blast happened said his windows were blown out.

The subdivision where the blast occurred was built in 2001, said resident Steve Belt. Belt said he was in bed with his wife when the explosion nearly knocked them out of bed, he said.

Belt was later escorted by police back inside his home for medication his wife needs because of a recent surgery.

As fire officials shut off gas to the neighborhood, police came by to evacuate residents to the elementary school staging area, where officials had established a triage area. There, after checking in with authorities, stunned neighbors sat on bleachers and waited for more information.

"You had a bunch of sleepy kids and nervous-looking parents," Patterson said.

Patterson and his wife ultimately spent the night at his mother's home.

As search and investigation efforts continue today, the Indianapolis Department of Code Enforcement will assess the safety of homes affected by the explosion.